Comparative mechanical property characterization of 3 all-ceramic core materials

Purpose: The biaxial flexural strength and fracture toughness for 3 represe ntative types of ceramic core materials were studied to iii ascertain the r anking of the 3 ceramic types for strength and toughness, and (2) provide c linicians with more information to predict clinical outcomes. The former ai m was deemed important in view of the importance of flaw size in the relati onship between failure stress and fracture toughness of brittle materials. Materials and Methods: The 3 representative ceramic types included a leucit e-reinforced glass, a glass-infiltrated sintered alumina, and a high-purity , high-density alumina. The biaxial flexural strength was measured with the piston-on-3-ball method. The plane-strain fracture toughness was measured with the short-bar chevron-notch method. Results: The biaxial flexural stre ngths of the high-purity, high-density alumina and glass-infiltrated sinter ed alumina ceramic core types were significantly higher than that of the le ucite-reinforced glass ceramic type. The glass-infiltrated sintered alumina was significantly higher in fracture toughness than the high-purity, high- density alumina type, which was significantly higher than the leucite-reinf orced glass. Conclusion: All materials surpassed the minimum strength requi rement outlined by the International Standards Organization, and they also had similar strength variability according to their Weibull moduli. The gla ss-infiltrated sintered alumina and the high-purity, high-density alumina t ypes were significantly stronger and tougher than currently used core mater ials. However, while the glass-infiltrated sintered alumina had a higher fr acture toughness than the high-purity, high-density alumina, it had a lower flexural strength.